The present invention relates generally to systems and methods for controlling fan speeds in a defined area. More particularly, the present invention relates to an anti-vibration system and associated methods for controlling fan speeds to reduce the impact of fan-induced vibrations in a server, a storage system, or in any other product containing vibration sensitive devices.
The storage systems industry has been plagued for years with issues of system performance being degraded by vibration sources external to the disk drives used in these sensitive systems. The ever-increasing data density of these disk drives means that they become even more sensitive to external vibration, especially on such systems as using for example the less-costly desktop disk drives in enterprise-level storage applications. The increased need for system cooling means that the system fan speeds increase annually, pushing the frequencies at which they emit vibrations into the range of sensitivity of the disk drives where the drive servo runs out of bandwidth. Consequently, server and storage applications have several sources of vibration that can potentially disturb the disk drives, a major source being the system cooling fans containing several different frequencies of vibration.
It is therefore desirable to mitigate the vibration effects on disk drives from power supply unit (PSU) fans or other system fans. Numerous methods have been introduced in the past to deal with this issue. One method is to isolate the fans entirely, but this method is not optimal in requiring sway space and additional components. Further, shock snubbing is also required. Another method involves providing improved one- or two-dimensional fan balancing to tighter limits, but this imposes substantial additional costs.
Yet another method which is particularly effective involves using three-phase fan motors, but again at a substantially higher cost. The structural stiffness or rigidity of the fans may be adjusted, but this requires additional design changes, development and accordingly time.
Damping methods may be incorporated to reduce resonant peaks in the fan frequencies, but the reduction in peaks is often insufficient to justify the additional costs involved.
It would therefore be desirable to introduce a system and method for reducing fan vibrations and the resultant effects or disturbances to disk drives, with a relatively minimal cost outlay.